A Metabolic Model for On-Line Estimation of Poly-β-Hydroxybutyrate (PHB) Production

Recently, the large scale production of Poly- β -hydroxybutyrate (PHB) by bacteria has become a subject of increasing interest. In the previous study, we found a constant flux to TCA cycle through isocitrate dehydrogenase under both balanced growth and nitrogen limiting conditions in fed-batch culture of A. eutrophus using the flux computation (Shi et al., 1997). The objectives of this study were to develop an effective monitoring system for the production of PHB based on the information obtained from metabolic flux analysis. A linear relationship among substrate consumption rate, oxygen consumption rate, and PHB production rate was obtained and further used for the on-line estimation of PHB production in fed-batch culture of A. eutrophus on butyrate.